Kam Leang 3D Printing Electroactive Polymer Soft Robots

August 24, 2016

Prof. Kam Leang - Soft Robotics
Mechanical engineering associate professor Kam Leang envisions a better robot made of just one material that moves without the use of motors and gears. And he won’t have to build it — he’ll just make it with a 3D printer.

It sounds like the stuff of science fiction. But Kam Leang’s research into “soft robotics” — in which robots made of soft polymers can move without motors — is quickly turning into science fact.

The University of Utah mechanical engineering associate professor has been developing new ways to create moveable objects from electroactive polymers that deform and change their shape when you stimulate them with electricity. Think of these materials moving much the same way as our muscles contract or move when they receive electrical impulses from the brain.

“We’re looking at alternatives to creating the traditional robot but making it more bio-inspired, more synthetic. It mimics what biological systems really are,” says Leang.

Since his graduate school days, Leang has been studying the use of ceramic as a smart material, figuring out how he can manipulate it in microscopic movements so it can perform tasks at the nanoscale. Recently, however, he has been working with electroactive polymer materials — such as Nafion by the chemical company, DuPont — that can deform by just hooking electrodes to it. Typically, Nafion is produced in sheets that look and bend like semi-clear plastic transparencies and are used as a membranes for fuel cells. But when immersed in water, the material can move like a muscle.

“When you soak it in water it becomes hydrated,” he explains. “If you apply an electrical field across it, the electrical field causes the ions in the polymer to move, and when they move, they bring the water with them to one side causing differential swelling. The swelling causes deformation such as bending.”

With just a small sheet of this material, Leang and his team created a fin that propelled a robotic fish. It didn’t require any motors, just a small battery that fed the fin electrical impulses that caused it to bend back and forth. But Leang is taking it further. His team has received a National Science Foundation Partnerships for International Research and Education grant to find new ways to manufacture and control the movement of objects out of Nafion and other similar electroactive polymer materials. The researchers recently built a 3D printer that can create movable objects out of the polymer material.

“Now you’re able to build soft robotic 3D structures like a soft robotic hand,” he says. So that’s what they did. The researchers printed a small hand with no motors or gears yet can move with electrical impulses.

With this technology, the applications could be limitless, Leang says. Prosthetics that function like real human limbs could be produced for amputees. Soft robots could replace certain stiff metallic machines for more delicate tasks such as working with physical-therapy patients. He also envisions smart materials being used in medicine for devices such as special catheters that need to bend and move as they navigate through the human body. Leang also is working with the U.S. Navy’s Office of Naval Research on developing a possible propulsion system for underwater machines that works like a flipper (and the robotic fish he created). Such a system would not require motors or moving parts and would use much less energy than fuel-powered propellers. Most importantly, this form of propulsion would be completely silent.

Best of all, Leang believes one day we could just print out the skeleton of a robot and it would immediately begin to work since there are no separate moving parts and no assembly.

“This is our goal: You have a 3D printer. You push the print button. It’s done, and a little robot walks out of the printer, fully printed,” he imagines. “Why is that important? Because you’re literally creating this moving, thinking object, and you’ve done it in a way that makes it easier for the user to create.”

Find the original story and more within the College of Engineering Annual Research Report 2016

To learn more about Prof. Leang and his research visit the DARC Lab (Design, Automation, Robotics & Controls).